A method and system for accurately positioning a robot for overhead power transmission lines

Abstract

The present invention discloses a precise positioning method and system for an overhead power transmission line robot, comprising: during the operation of the robot, image information of a set length of a power transmission line conductor is collected at set intervals, and the previous image and the next image collected in two adjacent time periods have a common area; the number of threads of the steel core aluminum stranded wire contained in the image of the next image without the common area is identified as the number of threads added or subtracted based on the position of the previous image; the position information of the robot is determined according to the number of threads finally obtained, the diameter of the steel core aluminum stranded wire and the thread pitch. The present invention can accurately judge the operation status of the robot by determining the position of the common area of ​​the previous image and the next image collected in two adjacent time periods.

Description

Technical Field

[0001] The invention belongs to the technical field of robot positioning, and in particular relates to a method and system for accurately positioning an overhead power transmission line robot. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] With the continuous development of robot technology and image recognition technology, special power robots are gradually replacing manual operations and becoming an important force in protecting the safe operation of power lines. Special line robots operate on overhead lines or other transmission lines and need to perform positioning measurement and navigation operations.

[0004] When the line robot runs close to the hardware obstacle, it needs to slow down in advance to prepare for the next obstacle crossing. When the robot is in the process of crossing the obstacle, it needs to perform different actions at different positions to complete the obstacle crossing. During the operation of the line robot, it also needs to accurately dock at a specific key point to complete the shooting of the line by the visible light camera and infrared camera carried by the robot. Therefore, accurate positioning of the robot running on the line is a very critical link.

[0005] The inventors found that most robots currently running on the line use GPS positioning and driven wheel encoders to locate their own positions. However, both methods have the problem of poor accuracy. The positioning accuracy of civilian GPS is only about five meters, and the driven wheel encoder method has the problem of slippage, making it difficult to achieve accurate positioning over long distances.

[0006] If the positioning is inaccurate, the line robot will have a serious collision accident, or even fall off the line. If the position error of the key point of the stop is large, the visible light camera and infrared camera cannot aim at the target to be photographed, and accurate line detection cannot be achieved. Summary of the invention

[0007] In order to solve the above problems, the present invention proposes a method and system for accurately positioning a robot on an overhead power transmission line, which accurately positions the robot running on the line according to the diameter and thread pitch of the steel-core aluminum stranded wire used in the transmission line.

[0008] In some embodiments, the following technical solutions are adopted:

[0009] A method for accurately positioning an overhead power transmission line robot, comprising:

[0010] During the operation of the robot, image information of a transmission line conductor of a set length is collected at set intervals, and the previous image and the next image collected in two adjacent time periods have a common area;

[0011] Identify the number of threads of the steel core aluminum stranded wire contained in the image without the common area in the latter image, as the number of threads to be added or subtracted based on the position of the former image;

[0012] The position information of the robot is determined according to the number of threads finally obtained, the diameter of the steel-core aluminum stranded wire and the thread pitch.

[0013] In other embodiments, the following technical solutions are adopted:

[0014] An overhead power transmission line robot precise positioning system, comprising:

[0015] The image acquisition device is configured to acquire image information of a set length of the power transmission line conductor at set intervals during the operation of the robot, wherein the previous image and the next image acquired in two adjacent time periods have a common area;

[0016] An image preprocessing device, configured to preprocess the acquired image;

[0017] The thread number recognition device is configured to recognize the number of threads of the steel core aluminum stranded wire contained in the image without the common area in the subsequent image as the number of threads to be added or subtracted based on the position of the previous image;

[0018] The positioning device is configured to determine the position information of the robot according to the number of threads finally obtained, the diameter of the steel-core aluminum stranded wire and the thread pitch.

[0019] Wherein, the image acquisition device comprises: a visible light source module and an image acquisition module;

[0020] The visible light source module comprises a light emitting diode, a first lens assembly and a reflector assembly; the visible light emitted by the light emitting diode reaches the aluminum stranded wire after being magnified by the first lens assembly and reflected by the reflector assembly, thereby providing a light source for image acquisition of the aluminum stranded wire;

[0021] The image acquisition module comprises a second lens assembly and an optical sensor; the image of the aluminum stranded wire in the illuminated area is acquired by the optical sensor.

[0022] In other embodiments, the following technical solutions are adopted:

[0023] A terminal device includes a processor and a computer-readable storage medium, wherein the processor is used to implement various instructions; the computer-readable storage medium is used to store multiple instructions, wherein the instructions are suitable for being loaded by the processor and executing the above-mentioned overhead power transmission line robot precise positioning method.

[0024] In other embodiments, the following technical solutions are adopted:

[0025] A transmission line image acquisition device, comprising: a visible light source module and an image acquisition module;

[0026] The visible light source module includes a light emitting diode, a first lens assembly and a reflector assembly; the visible light emitted by the light emitting diode reaches the power transmission line after being magnified by the first lens assembly and reflected by the reflector assembly, providing a light source for image acquisition of the power transmission line;

[0027] The image acquisition module includes a second lens assembly and an optical sensor; the image of the power transmission line in the illuminated area is acquired by the optical sensor.

[0028] In other embodiments, the following technical solutions are adopted:

[0029] An overhead power transmission line robot precise positioning system, comprising:

[0030] The above-mentioned image acquisition device is configured to acquire image information of a set length of the power transmission line conductor at set intervals during the operation of the robot, and the previous image and the next image acquired in two adjacent time periods have a common area;

[0031] The thread number recognition device is configured to recognize the number of threads of the steel core aluminum stranded wire contained in the image without the common area in the subsequent image as the number of threads to be added or subtracted based on the position of the previous image;

[0032] The positioning device is configured to determine the position information of the robot according to the number of threads finally obtained, the diameter of the steel-core aluminum stranded wire and the thread pitch.

[0033] In other embodiments, the following technical solutions are adopted:

[0034] A power transmission line inspection robot comprises: the above-mentioned overhead power transmission line robot precise positioning system.

[0035] In other embodiments, the following technical solutions are adopted:

[0036] A terminal device includes a processor and a computer-readable storage medium, wherein the processor is used to implement various instructions; the computer-readable storage medium is used to store multiple instructions, wherein the instructions are suitable for being loaded by the processor of the terminal device and executing the above-mentioned overhead power transmission line robot precise positioning method.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The present invention proposes a method for precise positioning of an overhead power transmission line robot and successfully develops a system suitable for precise positioning of an overhead power transmission line robot. By accurately identifying and screening statistics of images of overhead line conductors, the robot running on the overhead line conductors can accurately calculate the distance between the current position and the obstacle in front, and accurately complete the obstacle-crossing action during the obstacle-crossing process, thereby providing necessary guarantees for the reliable operation of the robot, overcoming the problem of the inability to accurately position the line robot due to the existence of cumulative errors during operation, ensuring the precise docking of the robot at key points when collecting images, and realizing millimeter-level positioning of the overhead power transmission line robot.

[0039] By determining the position of the common area of ​​the previous image and the next image collected in two adjacent time periods, the operation status of the robot can be accurately determined;

[0040] By identifying the number of aluminum strand threads that the robot passes through, the length of the aluminum strand can be accurately calculated, thereby achieving precise positioning of the robot.

[0041] The optical sensor is equivalent to a simple miniature camera. By collecting images through the optical sensor, it is convenient to use image processing methods to identify light and dark lines, and then screen and count them. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic diagram of the structure of an image acquisition device in Embodiment 1 of the present invention;

[0043] Figure 2 This is a flow chart of the precise positioning method of an overhead power transmission line robot in Embodiment 1 of the present invention;

[0044] Among them, 1. light emitting diode, 2. first lens assembly, 3. reflector assembly, 4. second lens assembly, 5. optical sensor, 6. aluminum stranded wire. DETAILED DESCRIPTION

[0045] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0046] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0047] Embodiment 1

[0048] In one or more embodiments, a method for accurately positioning an overhead transmission line robot is disclosed, referring to Figure 2 , because the conductors used in overhead lines are steel core aluminum stranded wires, which are twisted into a twist shape, and have a threaded structure on the outside, and the pitch between the two threads is fixed, that is to say, if the model of steel core aluminum stranded wire is determined, the diameter of the aluminum stranded wire and the pitch of the thread are determined. If the number of threads between two points of the steel core aluminum stranded wire is measured, the length of the aluminum stranded wire between the two points can be calculated. This can be applied to robots running on overhead lines, greatly improving the positioning accuracy of the robot on the line.

[0049] In this embodiment, the overhead transmission line robot precise positioning method specifically includes:

[0050] During the operation of the robot, the image information of a set length of overhead transmission line conductor is collected at set intervals, and by setting a suitable time interval, it is ensured that the previous image and the next image collected in two adjacent time periods have a common area;

[0051] Preprocess the collected images; first, perform overall edge detection on the collected images, detect the overall outline of the aluminum stranded wire, and extract the image of the aluminum stranded wire. The specific process is as follows:

[0052] (1) Gaussian blur denoising: Use Gaussian filter to smooth the detection image.

[0053] (2) Calculate the gradient magnitude and direction: Use the Sobel difference operator to calculate the gradient magnitude and direction. If the horizontal and vertical differences are expressed as Gx and Gy, the gradient magnitude G and direction θ are calculated as follows:

[0054]

[0055] θ=atan2(G y ,G x )

[0056] Non-maximum suppression edge refinement: Compare the gradient strength of the current point with the gradient strength of the points in the positive and negative gradient directions. If the gradient strength of the current point is the largest compared with the gradient strength of other points in the same direction, it is retained, otherwise it is suppressed.

[0057] The direction where the gradient amplitude increases is considered to be the positive direction, and the opposite direction is considered to be the negative direction. After the image is gradient calculated, the edge extracted based only on the gradient amplitude is still very fuzzy. Through non-maximum suppression edge refinement, it is determined whether the current gradient amplitude is a local maximum in the gradient direction, making the image edge clearer and sparser.

[0058] (3) Dual-threshold edge extraction: If the amplitude at a certain pixel position exceeds the set high threshold, the pixel is determined to be an edge pixel; if the amplitude at a certain pixel position is less than the set low threshold, the pixel is excluded; if the amplitude at a certain pixel position is between the two thresholds, the pixel is retained only if it is connected to a pixel above the high threshold.

[0059] After applying non-maximum suppression, the remaining pixels can more accurately represent the actual edges in the image. However, there are still some edge pixels caused by noise and color changes. Double threshold edge extraction is to resolve these stray responses and obtain the real edges.

[0060] The preprocessed image is subjected to straight line detection to identify the light and dark lines in the image, and the identified light and dark lines are screened to select the straight line segments that meet the thread direction and width of the aluminum stranded wire. The number of straight line segments that meet the thread direction and width of the aluminum stranded wire in the image is calculated, which is the number of threads in this image.

[0061] Identify the common area between the previous and next images. The specific method is:

[0062] For the first image, the set edge of the image is used as the edge of the matching template. On the first image, n pixels of width are intercepted in the direction of the other edge opposite to the set edge as the width of the template to form a matching template. Template matching is performed with the image block of width n in the second image. The sum of the differences in pixel values ​​at corresponding pixel positions is used as the judgment criterion. A judgment threshold is set. If the difference is less than the judgment threshold, the match is considered successful, otherwise the match is unsuccessful.

[0063] After the match is successful, the width value of the successfully matched image block in the second image, that is, the width of the overlapping area, is used as the width value of the common overlapping area.

[0064] Identify the number of threads of the steel core aluminum stranded wire contained in the image without the common area in the latter image, as the number of threads to be added or subtracted based on the position of the former image;

[0065] The position information of the robot is determined according to the number of threads finally obtained, the diameter of the steel-core aluminum stranded wire and the thread pitch.

[0066] The robot's moving direction is determined based on the position of the common area of ​​the images collected in two adjacent time periods. The robot's forward direction is set to the positive direction. When the common area includes the front end of the previous image, the robot's moving direction is forward, and the number of newly added threads is positive; when the common area includes the rear end of the previous image, the robot's moving direction is backward, and the number of newly added threads is negative.

[0067] In this way, the length of the aluminum stranded wire between two points is calculated based on the number of threads finally obtained, the diameter of the steel-core aluminum stranded wire, and the thread pitch, and then the position information of the robot is determined.

[0068] It should be noted that, in this embodiment, the method of the present invention is described by taking an overhead transmission line as an example, but this does not limit the protection scope of the present invention. The method of the present invention is also applicable to the precise positioning of a robot on other transmission lines in the form of aluminum stranded wires.

[0069] Embodiment 2

[0070] In one or more embodiments, a system for accurately positioning an overhead power transmission line robot is disclosed, comprising:

[0071] The image acquisition device is configured to acquire image information of a set length of overhead power transmission line conductor at set intervals during the operation of the robot, wherein a previous image and a subsequent image acquired in two adjacent time periods have a common area;

[0072] An image preprocessing device, configured to preprocess the acquired image;

[0073] The thread number recognition device is configured to recognize the number of threads of the steel core aluminum stranded wire contained in the image without the common area in the subsequent image as the number of threads to be added or subtracted based on the position of the previous image;

[0074] The positioning device is configured to determine the position information of the robot according to the number of threads finally obtained, the diameter of the steel-core aluminum stranded wire and the thread pitch.

[0075] Among them, the image acquisition device is as follows Figure 1 As shown, it includes: a light emitting diode 1, a first lens assembly 2, a reflector assembly 3, a second lens assembly 4 and an optical sensor 5.

[0076] Among them, the light-emitting diode 1, the first lens assembly 2 and the reflector assembly 3 constitute a light source that irradiates the aluminum stranded wire 6. The light-emitting diode 1 emits visible light, which is magnified by the first lens assembly 2 and reflected by the reflector assembly 3 to irradiate the aluminum stranded wire, illuminating a set area of ​​the aluminum stranded wire.

[0077] Because the light source is a light of a specific frequency, such as red light, it is easier to process the collected image information and can work without natural light. Due to the obstruction of the device itself, external light cannot directly reach the optical sensor. And because the light provided by the light source is a light of a specific frequency and is relatively strong, external light has little effect on the optical sensor.

[0078] The second lens assembly 4 and the optical sensor 5 form an image acquisition module, and the optical sensor 5 can acquire the image of the aluminum stranded wire 6 in the illuminated area.

[0079] Among them, the light-emitting diode 1, the first lens assembly 2, the reflector assembly 3, the second lens assembly 4 and the optical sensor 5 are all arranged in a plastic shell, and the entire image acquisition device is placed between the two walking wheels of the robot; as the robot walks, the image of the aluminum stranded wire can be collected during the movement.

[0080] It should be noted that the first lens assembly and the second lens assembly both include a lens and an attached lens fixing component, and the reflector assembly includes a reflector and an attached reflector fixing component.

[0081] In some other embodiments, a terminal device including the overhead transmission line robot precise positioning method described in Example 1 and a transmission line inspection robot including the overhead transmission line robot precise positioning system described in Example 2 are also disclosed.

[0082] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A method for accurate positioning of an overhead power transmission line robot, characterized in that: include: During the operation of the robot, image information of a transmission line conductor of a set length is collected at set intervals, and the previous image and the next image collected in two adjacent time periods have a common area; The method to identify the common area between the previous and next images is: For the first image, the set edge of the image is used as the edge of the matching template, and n pixels of width are intercepted in the direction of another edge opposite to the set edge on the first image as the width of the template to form a matching template; Perform template matching between the matching template and the image block of the second image with a width of n, take the sum of the pixel value differences of the corresponding pixel positions as the judgment criterion, set the judgment threshold, and consider the match to be successful if the difference is less than the judgment threshold, otherwise the match is unsuccessful; After the match is successful, the width value of the successfully matched image block in the second image is used as the width value of the common overlapping area; Identify the number of threads of the steel core aluminum stranded wire contained in the image without the common area in the latter image, as the number of threads to be added or subtracted based on the position of the former image; Determine the position information of the robot according to the number of threads, diameter of the steel-core aluminum stranded wire and thread pitch finally obtained; It also includes: preprocessing the collected images, specifically: Blur and denoise the image; Calculate the gradient magnitude and direction of the denoised image; Compare the gradient amplitude of the current point with the gradient amplitudes of other points in the same direction. If the gradient amplitude of the current point is the largest, keep the current point; otherwise, suppress the current point. Perform double threshold edge extraction: if the gradient amplitude at a certain pixel position exceeds the set high threshold, the pixel is determined to be an edge pixel; if the gradient amplitude at a certain pixel position is less than the set low threshold, the pixel is excluded; if the gradient amplitude at a certain pixel position is between the two thresholds, the pixel is retained only when it is connected to a pixel higher than the high threshold.

2. A method for accurate positioning of an overhead power transmission line robot as claimed in claim 1, characterized in that: The moving direction of the robot is determined according to the position of the common area of ​​the images collected in two adjacent time periods.

3. A method for accurate positioning of an overhead power transmission line robot as claimed in claim 2, characterized in that: The robot's forward direction is set to the positive direction. When the common area includes the front end of the previous image, the robot's moving direction is forward and the number of newly added threads is positive; when the common area includes the rear end of the previous image, the robot's moving direction is backward and the number of newly added threads is negative.

4. The method for accurate positioning of an overhead power transmission line robot according to claim 1, characterized in that: The method for determining the number of threads contained in the image is as follows: The preprocessed image is subjected to straight line detection to identify the light and dark lines in the image, and the identified light and dark lines are screened to select the straight line segments that meet the thread direction and width of the aluminum stranded wire. The number of straight line segments that meet the thread direction and width of the aluminum stranded wire in the image is calculated, which is the number of threads in the image.

5. A transmission line image acquisition device, which implements the overhead transmission line robot precise positioning method as claimed in any one of claims 1 to 4, characterized in that: include: Visible light source module and image acquisition module; The visible light source module includes a light emitting diode, a first lens assembly and a reflector assembly; the visible light emitted by the light emitting diode reaches the power transmission line after being magnified by the first lens assembly and reflected by the reflector assembly, providing a light source for image acquisition of the power transmission line; The image acquisition module includes a second lens assembly and an optical sensor; An optical sensor captures images of the illuminated area transmission lines.

6. An overhead power transmission line robot precise positioning system, characterized in that: include: The image acquisition device of claim 5 is configured to acquire image information of a set length of the power transmission line conductor at set intervals during the operation of the robot, and the previous image and the next image acquired in two adjacent time periods have a common area; The thread number recognition device is configured to recognize the number of threads of the steel core aluminum stranded wire contained in the image without the common area in the subsequent image as the number of threads to be added or subtracted based on the position of the previous image; The positioning device is configured to determine the position information of the robot according to the number of threads finally obtained, the diameter of the steel-core aluminum stranded wire and the thread pitch.

7. A power transmission line inspection robot, characterized in that: include: The overhead power transmission line robot precise positioning system as described in claim 6.

8. A terminal device, comprising a processor and a computer-readable storage medium, wherein the processor is used to implement each instruction; and the computer-readable storage medium is used to store multiple instructions, characterized in that: The instructions are suitable for being loaded by a processor of a terminal device and executing the overhead power transmission line robot precise positioning method described in any one of claims 1-4.

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